Off grid solar

[ggunn]

If you’re using the grid then you aren’t “off grid”
That would be more of a hybrid application.

Agreed. Living truly off grid means working without a net.

 

[caribconsult]

If you’re using the grid then you aren’t “off grid”
That would be more of a hybrid application.

I guess that's somewhat true. We aren't totally off grid. In fact, yesterday was a good example....there was good sunlight in the morning, but by mid day, it had clouded over and started to rain heavily and the battery had only reached 68% by that time...not enough to carry us through the rest of the day and into the next, so we switched on the grid, let the battery charge up and between the approximately 5Kwh of grid we used and the limited amount of solar still availably, by sundown we had a full battery. I suppose we could have used the generator to run the house until dark and then switched over to the battery, and it might have made it through the night. For the approximately $1.65 worth of grid we used, it was worth it to not have to listen to the generator! In the tropics where we live, afternoon rainstorms are fairly common, especially during the summer, so this happens perhaps once or twice a week, depending on the weather. Much less frequent during the fall and winter. We're fine with it. Our grid bill averages $15-20 month and rates just went up again.

 

[ggunn]

I guess that's somewhat true. We aren't totally off grid.

More than somewhat. If you were living off grid you would have challenges to deal with that are not a concern to you as long as you have the safety net of throwing a switch to connect your home to the grid when your distributed generation system fails to keep up with your consumption.

Aside: what would you estimate the all-in cost per kWh of the energy you are producing and storing on site?

 

[caribconsult]

More than somewhat. If you were living off grid you would have challenges to deal with that are not a concern to you as long as you have the safety net of throwing a switch to connect your home to the grid when your distributed generation system fails to keep up with your consumption.

Aside: what would you estimate the all-in cost per kWh of the energy you are producing and storing on site?

Well, according to the app we are about 99.99% self powered, so the little bit we use from the grid just gives us peace of mind. You're probably right calling it a hybrid system. If we didn't have the grid, we'd use our generator if there wasn't enough sun, but that has happened perhaps twice in the almost 5 years we have the Tesla system. The extra challenge is finding gasoline when everything is closed! Based on the current rates from the PoCo, ($0.32/Kwh, including fuel surcharges, and soon to go up) the app says the value of what we've generated this year is worth about $896, which sounds right. We're now in month 8 and our electric bill used to be a bit over $110/month, but the money wasn't our first objective - it was peace and quiet and getting off the grid due to a mountain of fried gear from grid surges, etc. Today might be another day we'll need some grid...the battery is at 88%, it's 2:30pm and it's raining out and looks to be raining all afternoon, so I don't think there's any more solar today. So we'll probably turn on the grid around sundown and get the battery up to about 85%

 

[ggunn]

Well, according to the app we are about 99.99% self powered, so the little bit we use from the grid just gives us peace of mind. You're probably right calling it a hybrid system. If we didn't have the grid, we'd use our generator if there wasn't enough sun, but that has happened perhaps twice in the almost 5 years we have the Tesla system. The extra challenge is finding gasoline when everything is closed! Based on the current rates from the PoCo, ($0.32/Kwh, including fuel surcharges, and soon to go up) the app says the value of what we've generated this year is worth about $896, which sounds right. We're now in month 8 and our electric bill used to be a bit over $110/month, but the money wasn't our first objective - it was peace and quiet and getting off the grid due to a mountain of fried gear from grid surges, etc. Today might be another day we'll need some grid...the battery is at 88%, it's 2:30pm and it's raining out and looks to be raining all afternoon, so I don't think there's any more solar today. So we'll probably turn on the grid around sundown and get the battery up to about 85%

I wasn't asking what the energy would have cost if you bought it from the grid; I was asking you what you are actually paying for it, i.e., what the equipment cost is amortized over, say, 20 years, with added expenses for maintenance and anticipated equipment replacement, divided by the number of kWh you expect it to produce over the life of the equipment. That is, your real cost per kWh.

Of course, where you are in Puerto Rico with energy as expensive as it is along with the stories I have heard about how stable the grid there is (or isn't), the economics would be very different for you than for me.

 

[gadfly56]

I wasn't asking what the energy would have cost if you bought it from the grid; I was asking you what you are actually paying for it, i.e., what the equipment cost is amortized over, say, 20 years, with added expenses for maintenance and anticipated equipment replacement, divided by the number of kWh you expect it to produce over the life of the equipment. That is, your real cost per kWh.

Of course, where you are in Puerto Rico with energy as expensive as it is along with the stories I have heard about how stable the grid there is (or isn't), the economics would be very different for you than for me.

No doubt. Replacing all your electrical and electronic appliances every few months probably adds up.

 

[caribconsult]

No doubt. Replacing all your electrical and electronic appliances every few months probably adds up.

OK, I didn't quite understand what you (ggunn) were asking. We paid about 25K for the system, including installation, and although we thought we were going to get the 30% Federal Tax Credit, it turns out that doesn't apply in Puerto Rico. We have 21 panels (250w was the standard then) one battery and the gateway, and the installation was excellent. When we were having issues at the beginning, they gave us and installed an Enphase Envoy to monitor things, free of charge...that was nice. The Envoy really lets you keep an eye on your PV setup....these should be mandatory for a solar system. So we paid top dollar, but it was immediately after hurricane Maria, and everyone wanted one of these. It took almost 3 months for it to arrive here and to get it installed. I'd say considering what we save on the electric bill, which keeps going up and service gets worse, there's about a 20 year time frame for it to pay for itself, but as I said, the money was secondary. Considering the system saves us over $1,200 per year on electric, the investment is paying off at around 5%, which isn't too bad these days. We've had no maintenance issues with it, gratefully, and I have an excellent relationship with Tesla's top sales and engineering staff here in the Caribbean, so service hasn't been an issue. And as was noted, replacing microwaves, cell phones, TV's, a home stereo, satellite receivers, computers, monitors, routers, etc, adds up over time. I even have a little digital voltmeter on the PoCo side of the wiring to see what their voltage is, and a lightning strike a few days ago about 100 yards from the house blew it out, probably an inducted surge through the grid line. It's the only thing around here besides the meter connected full time to the PoCo!. The PoCo even had to replace our meter about 2 years ago...it blew out, probably from another surge or jolt. One of the reasons we didn't go for a net-metering setup. We've lost nothing inside the house since we put in the Tesla, so there's a value on that, not to mention the inconvenience of replacing all this stuff. The local PoCo is beyond description....dimwit technicians, obsolete equipment, vulnerable wiring, poles that fall over, surges, jolts, inducted shocks from nearby lightning strikes (we're in a serious lightning zone) black and brown outs....the less we have to deal with them the better, and the Tesla gives us that little goody as well. How do you put a price on that? Feel free to ask more questions.

 

[ggunn]

OK, I didn't quite understand what you (ggunn) were asking. We paid about 25K for the system, including installation, and although we thought we were going to get the 30% Federal Tax Credit, it turns out that doesn't apply in Puerto Rico. We have 21 panels (250w was the standard then) one battery and the gateway, and the installation was excellent. When we were having issues at the beginning, they gave us and installed an Enphase Envoy to monitor things, free of charge...that was nice. The Envoy really lets you keep an eye on your PV setup....these should be mandatory for a solar system. So we paid top dollar, but it was immediately after hurricane Maria, and everyone wanted one of these. It took almost 3 months for it to arrive here and to get it installed. I'd say considering what we save on the electric bill, which keeps going up and service gets worse, there's about a 20 year time frame for it to pay for itself, but as I said, the money was secondary. Considering the system saves us over $1,200 per year on electric, the investment is paying off at around 5%, which isn't too bad these days. We've had no maintenance issues with it, gratefully, and I have an excellent relationship with Tesla's top sales and engineering staff here in the Caribbean, so service hasn't been an issue. And as was noted, replacing microwaves, cell phones, TV's, a home stereo, satellite receivers, computers, monitors, routers, etc, adds up over time. I even have a little digital voltmeter on the PoCo side of the wiring to see what their voltage is, and a lightning strike a few days ago about 100 yards from the house blew it out, probably an inducted surge through the grid line. It's the only thing around here besides the meter connected full time to the PoCo!. The PoCo even had to replace our meter about 2 years ago...it blew out, probably from another surge or jolt. One of the reasons we didn't go for a net-metering setup. We've lost nothing inside the house since we put in the Tesla, so there's a value on that, not to mention the inconvenience of replacing all this stuff. The local PoCo is beyond description....dimwit technicians, obsolete equipment, vulnerable wiring, poles that fall over, surges, jolts, inducted shocks from nearby lightning strikes (we're in a serious lightning zone) black and brown outs....the less we have to deal with them the better, and the Tesla gives us that little goody as well. How do you put a price on that? Feel free to ask more questions.

Can you distill that down to ~$/kWh? That's the real question for most people considering living off grid when the grid is available.

 

[caribconsult]

Can you distill that down to ~$/kWh? That's the real question for most people considering living off grid when the grid is available.

Sorry, I'm not a math major and I'm not quite sure how I'd computer $/Kwh, since we paid for the whole system years ago, and I don't know what our consumption would be for 20 years. I've given you about all the data I have in terms of our bill, percent of self-powered use, etc. I know it saves us over $1,200 per year, probably more with the tariff increases we've had recently and no doubt will continue. That's about a 5% non-taxable return per year over 20 years, which isn't easy to find in the stock market. And the cost of replacement of all the burnt out stuff isn't even included in that figure but it's not be be ignored. The $/Kwh figure is not something we've given a lot of thought to. You're welcome to figure it out if you can!

 

[caribconsult]

Can you distill that down to ~$/kWh? That's the real question for most people considering living off grid when the grid is available.

I did some further checking, and took a close look at my electric bill from the PoCo. They charge $4 to have the connection, $.049/Kwh basic consumption charge, plus another almost $.23/Kwh in fuel charges and assorted other charges, and it adds up to about $0.39/Kwh for a low consumption like ours (43Kwh last month), so the savings are about $1,000 year to date and we still have 4+ months to go. The ROI is a bit better...maybe 5.5%. Since the $4 connect charge is fixed, the more Kwh you use, the lower the actual cost per Kwh, but it's still probably in the vicinity of $0.32/Kwh if we were using 550+Kwh as we used to, so we save all that, in addition to the convenience and other matters I mentioned. This is probably the most accurate numbers I can give you.

 

[caribconsult]

If you’re using the grid then you aren’t “off grid”
That would be more of a hybrid application.

We're 'off grid' except when we need it. So you could call it a hybrid system, but we're off grid about 99.99% of the time. That's good enough for me. As I noted, you can't live on the sun if there isn't any, and for example, this month of August, 2022, we've had extended afternoon rain almost every day. Normally, the house would run on the PV array from around noon (full battery) until sundown, about 6pm here in the tropics. This year we've had a very rainy August and so we windup using a bit of grid to supplement the sun we aren't getting in the afternoon. When you add the year up, it's still a tiny percentage of our total use. And yesterday, there was minimal sun AND the grid was down (not unusual here in PR) so we wound up running our gen until about 8pm, the Tesla reaped another few percent during the cloudy afternoon, and then we switched over to the battery which had about 68% charge at that point and got us through the night. Good sun today, battery is charging well. So call it what you want....we save over $100/mon in grid bill, that's going to increase since our local PoCo has had 7 rate boosts in the last year and a half, and we always have mostly silent power one way or the other. If you want to talk about return on investment, we spent about 25K on this system, and it saves us over $1,200 a year (and that will increase as our PoCo continues to raise rates), about a 5% return, tax free. That's not a bad investment these days. How much more do you want from a solar system?

 

[ggunn]

We're 'off grid' except when we need it. So you could call it a hybrid system, but we're off grid about 99.99% of the time.

I think the point was that if you have the grid as a safety net you are not truly off grid. If you don't have the grid as a backup it complicates things. It's great that you don't need it most of the time but if you do it's there. If you didn't have grid access then if/when you exhausted your batteries you would be in the hot/cold dark with your food spoiling.

 

[electrofelon]

I think the point was that if you have the grid as a safety net you are not truly off grid. If you don't have the grid as a backup it complicates things. It's great that you don't need it most of the time but if you do it's there. If you didn't have grid access then if/when you exhausted your batteries you would be in the hot/cold dark with your food spoiling.

Its easy to live off grid "most" of the time.

 

[caribconsult]

I think the point was that if you have the grid as a safety net you are not truly off grid. If you don't have the grid as a backup it complicates things. It's great that you don't need it most of the time but if you do it's there. If you didn't have grid access then if/when you exhausted your batteries you would be in the hot/cold dark with your food spoiling.

I agree...we're not totally off grid and we don't feel a need to be, since it's right here and we have a legit account. We're hybrids.

Your comment points out exactly why we didn't give up the generator. The installer for the Tesla originally wanted to set it up so we couldn't use the gen and I told him that wasn't going to happen...all it took was another switch to add the gen connection and bypass the Tesla and the grid, and he figured it out and they threw in the switch free. We used it yesterday when there was no sun, no grid service and the battery was down to 62% and it was still the middle of the day. We just saved the battery for the overnight so we wouldn't have to listen to the gen and ran on it until about 8pm, then shut it off and switched over to the Tesla. Then the grid returned so we closed the grid breaker and used that to charge up the battery to where it should have been at that time of night, then shut that off and went to bed. Today the grid is working but not connected, the sun is out and the battery is up to 86% and there's almost 5Kw coming from the PV array. Might have used 2 gallons of gas. Def worth $8.

 

[gadfly56]

I agree...we're not totally off grid and we don't feel a need to be, since it's right here and we have a legit account. We're hybrids.

Your comment points out exactly why we didn't give up the generator. The installer for the Tesla originally wanted to set it up so we couldn't use the gen and I told him that wasn't going to happen...all it took was another switch to add the gen connection and bypass the Tesla and the grid, and he figured it out and they threw in the switch free. We used it yesterday when there was no sun, no grid service and the battery was down to 62% and it was still the middle of the day. We just saved the battery for the overnight so we wouldn't have to listen to the gen and ran on it until about 8pm, then shut it off and switched over to the Tesla. Then the grid returned so we closed the grid breaker and used that to charge up the battery to where it should have been at that time of night, then shut that off and went to bed. Today the grid is working but not connected, the sun is out and the battery is up to 86% and there's almost 5Kw coming from the PV array. Might have used 2 gallons of gas. Def worth $8.

Your experience highlights both the advantages and difficulties of trying to set up off-grid, or near off-grid configurations. You have tremendous flexibility, but you are likely very nearly a one-in-a-million user who is sophisticated enough to make this work. Imagine getting your average hedge fund broker, or anyone else with the scratch to spare, up to speed on this system and then maintaining the competence to run it. The only thing my electrical system needs from me is to remember where the switches are. When it gets that easy, there's hope for widespread adoption, money permitting, but not before then.

 

[caribconsult]

Your experience highlights both the advantages and difficulties of trying to set up off-grid, or near off-grid configurations. You have tremendous flexibility, but you are likely very nearly a one-in-a-million user who is sophisticated enough to make this work. Imagine getting your average hedge fund broker, or anyone else with the scratch to spare, up to speed on this system and then maintaining the competence to run it. The only thing my electrical system needs from me is to remember where the switches are. When it gets that easy, there's hope for widespread adoption, money permitting, but not before then.

I couldn't agree more! Our setup is def not for the average homeowner. Although it can be completely controlled with just three switches, and only two if the gen isn't involved, it requires an understanding of the seasonal sun patterns, the household draw, what looks normal vs what doesn't, how to interpret the readings from the app, etc. I don't recommend it for anyone who doesn't have the time to learn the system. Def easier to just leave the grid on and use the solar as backup, but that doesn't save you much, if anything on your electric bill. I'm not an electrician but I am competent to wire a house, repair almost anything electrical without killing myself, and I wanted to learn how to run this rig and I'm glad we went the way we did...I'd do it again in a heartbeat, but as you so accurately pointed out, it's not for the average Joe. If we're traveling and having someone stay at our house, I generally just switch on the grid feed and tell them don't worry about it. We do have one friend who's stayed at our house several times and he's actually getting the feel of the system and how to use the app, so it's not rocket science but it does take some effort and thinking. The saying down here is "cada loco con su tema," which roughly translates to "everyone has their own way of doing things."

 

[caribconsult]

OK, I don't want to get into a grammatical debate here...our system is def a hybrid in the sense that the grid is available, although we barely use it. Just to point out how all things need to be considered, we are right now recovering from a hurricane (Fiona) and the grid is down island-wide. There hasn't been any sun for three days and likely not until tomorrow at the earliest. Our battery is holding at 43% but that's not enough to safely get us from sundown until sun up tomorrow, if in fact there is any sun. The Tesla is disconnected from the house and idling but charging if any sun comes out or even just bright light. We are using a genenerator, it is wired into the main panel via a switch which ensures that the grid is disconnected at the same time, have been using it for two days and we have enough power to live normally. So I'd characterize our system as multi-source, not merely hybrid. Unlike gasoline, you can't go to the local service station and buy more sunlight.

 

[retirede]

OK, I don't want to get into a grammatical debate here...our system is def a hybrid in the sense that the grid is available, although we barely use it. Just to point out how all things need to be considered, we are right now recovering from a hurricane (Fiona) and the grid is down island-wide. There hasn't been any sun for three days and likely not until tomorrow at the earliest. Our battery is holding at 43% but that's not enough to safely get us from sundown until sun up tomorrow, if in fact there is any sun. The Tesla is disconnected from the house and idling but charging if any sun comes out or even just bright light. We are using a genenerator, it is wired into the main panel via a switch which ensures that the grid is disconnected at the same time, have been using it for two days and we have enough power to live normally. So I'd characterize our system as multi-source, not merely hybrid. Unlike gasoline, you can't go to the local service station and buy more sunlight.

I thought about you when I saw Fiona’s path. Hope everyone stays safe!

 

[gadfly56]

I thought about you when I saw Fiona’s path. Hope everyone stays safe!

Me too. I was going to drop a PM today to see how things are. With everything so trashed, I'm surprised carib has internet connectivity.

 

[caribconsult]

Thanks for thinking of us, folks. Fiona wasn't anything like Maria, 5 years ago. 85mph winds instead of 140mph makes a big difference. But our trusty generator has been doing yeoman duty...we'd have no power or water otherwise. The muni water is also off and if we have no power, our pump won't work, so it's a double whammy. Our understanding is they frequently shut off the utils in anticipation of a storm, thinking that may minimize damage. I can't weigh in on the effectiveness of that strategy. From what we've heard about trees down, it may be a week or more before the grid is restored, possibly even longer. We're praying for some sun soon. Our internet, cellphones and satellite TV all have been working through the storm, so we don't have that 'cut off' feeling.